Screening device



April 17, 1962 A- J. ROUBAL SCREENING DEVICE Filed Aug. 31, 1959 3,029,945 fiCREENING DEVI- IE Atexander .l'. Roubai, Milwaukee, Wis, assiguor to Allis- (Ihaimers Manufacturing Company, Miiwaukee, Wis. Filed Aug. 31, 1959, er. No. 837,268 2 Claims. (Cl. 209326) This invention relates generally to screening machines or devices for use in connection with screening and separating of materials, and like operations.

More particularly, this invention relates to improve ments in gyratory screening machines of the four-bearing double-throwshait type resulting from providing each of tlheouter bearing housings with a pair of oppositely extending elongated arms and then hanging these arms and the screen body from a stationary overhead supporting structure with a plurality of strategically disposed resiliently based cable means, each means being independent of every other means. In this fashion, I provide a device in which the cyclic forces resulting from the movement of the gyrating body and of the outer bearing housings during operation of the device are substantially completely balanced relative to the overhead structure from which the device is hung and the massive and expensive bottom frame, which characterized the prior art devices, is eliminated.

For purposes of this description, a four bearing screen may be considered as being, in part, a conventional two bearing screen having two running shaft projections extending outside of its balance wheels. Such a two bearing screen, however, becomes a four bearing unit because these shaft projections are journaled into outer bearings. In prior art machines, as exemplified by Parks, U.S. 2,212,550, these outer bearings, in turn, are carried on a massive stationary frame which is rigidly secured to the building in which the screen is operated.

The present invention is predicated upon my discovery that the massive and expensive supporting frame heretofore required (for instance, see the aforementioned patent to Parks) can be eliminated and excellent operational characteristics obtained by the combined action of suspending the soreen body itself with resiliently based cable means from an overhead supporting structure, and, independently thereof, also suspending outer bearing housing extensions directly from the same overhead supporting structure with like resiliently based cable means. In

a new design for a four-bearing screen having a doublethrow-shaft in which vibrations of its operation are separated from the stationary supporting structure from which it is suspended by the strategic placement of resiliently .based cable means therebetween.

- Another object of the present invention is to provide a new design for a four-bearing screen having a doublethrow-shatt in which balance between the screen body and special extensions outreaching from outer bearing housings is obtained by the compensation of the out of phase action of these members during the operation thereof.

Still another object of the present invention is the provision-of a balanced four bearing screen, of the type described, in which the vibratable body and special exten- 3,029,945 Patented Apr-. 17, 19s2 sions of the outer bearing housing are independently suspended from a common overhead supporting structure.

A still further object of the present invention is to provide a new design for a four-bearing screen having a double-throw-shaft in which complete balance is obtained with the omission of the stationary frame therefrom.

A still further object of the present invention is to provide an improved balanced four bearing screen which is easier and more economically produced, which provides easier access for repair and maintenance, which may have its slope readily changed by but minor adjustments, which liberates valuable fioor space for the use of other equipment, which permits the close positioning of auxiliary equipment such as conveyer and the like to efiiciently utilize available space, which-reduces. dust hazards re sulting from extended free falling of graded material through space, and which is more compact, than such screens hereto-fore available.

These and still further objects, as shall hereinafter appear, are fulfilled by the present invention in a manner which may be easily discerned from the following detailed description of an exemplary device embodying the present invention, especially when the description is read in conjunction with the accompanying drawing.

In the drawing in which like parts bear like numerals throughout the several views:

' FIG. 1 is a side elevation of a screening device embodying the present invention; and

FIG. 2 is an end elevation of the screen.

By way of example, one embodiment of my invention is shown in connection with an apparatus for screening materials in which the numeral 11 indicates the stationary overhead supporting structure'which may consist of a plurality of I-beams 1.2 or like members, which may either be a portion of or carried by the building in which the device will be operated. I I Numeral 14 indicates the screen body which is suspended from support means 11 by a first plurality of resiliently based cable means 15 to b'ephereinaiter more fully described. As shown in FIG. 1, the screen body 14 is inclined in the conventional manner to permit the flow of material thcrethrough and is provided with one or more screen decks 16 having the usual toraminous surface for grading and, separating material directed thereupon. It is, of course, understood that any desired number or type of screen deck may be employed according to the exigencies of the operations without departing from the intended scope of this teaching. 7

The screen body 14,-as shown, further includes upwardly extending side plates 19, 20 which reachabove screen deck' 16 to prevent the lateral fall of material therefrom; and backing plate 21, which prevents spillage of material from the deck 16 at the feed end of the screen. Screen decks 16 are normally attached to the side plates 19, 20.

At the discharge end of the screen, suitable openings 22 are provided for each deck 16 to permit the flow of graded material from the screen deck into a desired continuation of the unit process involved such, for example, as a conveyer, a scrubber and the like. Of course, the bottom of body 14 is open, in the usual fashion, to permit the passage or" undersize material therethrough.

The means for gyrating the screen body are normally constructed as follows: the screen body 14 is balanced or supported for gyratory movement midway of its ends on a transverse driving shaft 25which passes through the side fashion in and by companion gyratory supporting bodies or bearings 32, 33 (herein called outer bearings).

To put it still another way, drive shaft is continuous and is provided adjacent each of its opposite ends with journal portions 28, 29 which are respectively mounted within inner bearings 26, 27 fitted respectively in the adjoining side walls 19, 20 of the screen body 14. Journal portions 28, 29, respectively, extend therefrom through suitable inertia controlling means, such as flywheels 30, 31, into outer bearings 32, 33. Bearings 32, 33, which are in register with each other, are outboard of bearings 26, 27 and, therefore, are called outer bearings." The axis of the register of outer bearings 32, 33 is, however, offset from the axis of register of inner bearings 26, 27 by the amount of eccentricity desired in the shaft which, in double throw shafts, is equal to the total throw desired in the screen body.

Each of the outer bearings 32, 33 is enclosed by a suitable outer bearing housing 34, 35, respectively, Each outer bearing housing, for example, housing 34, is provided with a pair of outwardly extending arm portions or extensions 38, 39, the full significance of which will be more fully explained. Similar arms 38a, 39a extend from housing 35.

One end of shaft 25, for example, the end having journal portion 28 and passing through inner bearing 26, flywheel and outer bearing 32, is provided with a further extension 41 to which a pulley 42 is secured and drivingly connected, as with V-belts 43, to a suitable source of power such as motor 44. Motor 44 may be mounted in any desirable location which is operative with pulley 42 such, for example, as to supporting structure 11. As shown, shaft extension 41, that is, the pulley receiving portion of the shaft 25, is concentric with the actual center thereof. Motor 44 may comprise any suitable source of motive power although electrical motors are generally preferred.

Gyration of the screen body 14 is thus readily achieved by the actuation of the motor 44 which, in turn, drives sheave 42 through linkage 43 whereby shaft 25 is rotated in bearings 26, 27, 32, 33 and with flywheels 30, 31 to impart gyratory movement to decks 16.

Referring again to the outer bearing housings previously introduced, each housing (considering housing 32 as exemplary), is, as previously described, provided with outreaching arms or extensions 38, 39 which extend from opposed peripheral portions of the housing 32. Each of the arms 38, 39 extends generally longitudinally of the screen body 14 and terminates adjacent the ends thereof such as is shown in FIG. 1. Of course, a like construction is provided on the opposite side of the screen body 14 where arms 38a, 39a extend from hearing housing 33.

Adjacent the ends of each arm (considering arm 38 as typical) suitable hitching means, such as, for example, U-bolt 47 are provided which are adapted for hitching a cable means 48 to arm 38. In the embodiment shown, cable means 48, which are mounted to and depend from support means 11 in a fashion to be more fully described, include an elongated shank portion 49 having eye means 49a defined at one end thereof through which U-bolt '47 is fed prior to being secured to arm 38 in a suitable fashion as with nuts 47a. It is, of course, understood that any of the well known means of joining two parts to provide the desired freedom of movement may be used.

Another important feature of the present invention resides in the manner by which cable means 48 are resiliently based. Thus, shank portion 49 extends upwardly through the overhead supporting structure 11 where it is resiliently secured by the coaction of a base plate 50, a spring 51, and a retaining plate 52, all of which circumscribe shank 49 and which are secured in assembled condition by suitable locking means such, for example, as lock nuts 53. In this fashion, cable means 48 react upon retaining plate 52 which bears upon 'base plate 50 through spring 51 to provide a resilient base for the cable means '48.

Like hitching means are similarly provided for each of the several housing arms and, in a like fashion, have independent resiliently based cable means connected thereto for suspending the arms from the overhead support structure 11.

Another important aspect of the present invention thus presents itself in that each outer bearing housing is provided with a pair of outwardly extending arms which, adjacent their respective ends, are connected, independently of each other, to an overhead supporting structure by resiliently based cable means. It is further important that the cable means 15, which, as will appear, extend between supporting means 11 and screen body 14 are likewise independent of each other and of the cable means corresponding to cable means 48. Cable means 15, which suspend the screen body 14 from the supporting structure 11 through, preferably, a common base plate 50 (although each may have its own base plate placed in close proximity to the plates of the cable means 48 adjacent thereto), similarly comprise a shank portion 55 extending upwardly through overhead supporting structure 11 and resiliently based thereupon by a spring 56 sandwiched between base plate 50 and retaining plate 57, all of which circumscribe shank 55 and which are locked into their assembled positions by a suitable lock nut 58 threaded upon shank portion 55 and abutting retaining plate 57. Shank portion 55 is provided at its other end with suitable means, such, for example, as clevis 59 for attachment directly to side plates 19, 20 of screen body 14 in a manner which provides two cable means secured to the top edge of each of the side plates 19, 20, one being adjacent each end thereof as shown.

It should be noted, and can be readily detected in FIG. 1 of the drawing, that the angle of inclination or slope of my screen may be easily adjusted through the simple expedient of tightening or loosening (depending whether it is desired to raise or lower the end of the screen) the lock nuts 58 of each of the cable means 15 adjacent the end of screen body 14 whose movement is desired. Similar adjustments can be performed with equal ease upon each of the cable means 48 by adjusting the appropriate lock nut 53.

In operation, the screen body 14 and the outer bearing housings 34, 35 gyrate in response to the actuation of motor 44 and, because of the proper static balance provided by flywheels 30, 31 in the usual manner, move at approximately degrees out of phase with each other. This out of phase movement of the body and the housings creates opposing force moments relative to the locus of the adjacent cable means. If each load were plotted, it would be found that they load structure 11 with a cyclic or, more specifically, a sinusoidal load. However, with the novel placement and coaction of my resiliently based cable means and the structure associated therewith in the manner described, the cyclic load is effectively transformed into a substantially uniform load relative to the supporting structure which is maintained upon the supporting structure irrespective of the cyclic loading placed on the cables by the device. Thus, the deleterious shock which would otherwise be placed upon the supporting structure is substantially completely eliminated and the heavy supporting frames heretofore required are expurgated from four-bearing double-throw-shaft screen design.

It thus becomes apparent that the screening device herein described and illustrated fulfills the aforestated objectives to a remarkably unexpected extent and that a new screen of vastly improved design has been created which greatly advances the art relative thereto.

It is, of course, understood that the embodiments herein described and illustrated are presented to illustrate rather than limit the present invention; and that all modifications, alterations and applications which employ the novel conceptsherein introduced to the art of vibrating screens and analogous equipment are intended within the spirit of the present invention, especially as it is defined by the claims appended hereto.

What is claimed is:

l. A screening device comprising: stationary support means; a generally rectangular vibratory body disposed beneath said support means; a first set of bearings carried by body in spaced opposed registry with each other; a second set of bearings disposed outboard of said body in spaced opposed registry with each other offset from said registry of said first set of bearings; a horizontally extending continuous gyrating shaft engaging said first and said second set of bearings and extending through said body to impart gyratory movement thereto; a bearing housing disposed about each of said second set of bearings and having a first and second outreaching arm portion extending from opposed portions of said housing; a first set of four cable means connected one to each of said arm portions adjacent the end thereof and extending parallel upwardly therefrom through said support means; a second set of four cable means connected one adjacent each of the corners of said generally rectangular body at the sides thereof and extending parallel upwardly therefrom through said support means; and an independent resilient base means connecting each one of said cable means of both sets to independently and resiliently connect said cable means to said support means.

2. A screening device comprising: stationary support means; a generally rectangular vibratory body disposed beneath said support means and having substantially parallel side Walls and end walls; a first set of bearings carried by body in spaced opposed registry with each other;

a second set of bearings disposed outboard of said body in spaced opposed registry with each other offset from said registry of said first set of bearings; a horizontally extending continuous gyrating shaft engaging said first and said second set of bearings and extending through said body to impart gyratory movement thereto; a bearing housing disposed about each of said second set of bearings and having a first and second outreaching arm portion extending from opposed portions of said housing, with each arm reaching substantially more than one-half the distance toward one of said end walls; a first set of four cable means connected one to each of said arm portions adjacent the end thereof and extending parallel upwardly therefrom through said support means, each cable of said first set being connected sufficiently close to the end of the arm to which it is connected so that the connection therebetween is spaced away from the shaft more than one-half the distance toward one of said end walls; a second set of four cable means connected one adjacent each'of the corners of said generally rectangular body at the sides thereof and extending parallel upwardly therefrom through said support means; and an independent resilient base means connecting each one of said cable means of both sets to independently and resiliently connect said cable means to said support means.

References Cited in the file of this patent UNITED STATES PATENTS 2,230,316 Wolz Feb. 4, 1941 2,246,483 Dillon June 17, 1941 2,313,765 Parks Mar. 16, 1943 

